Most closure or cut-off devices are awkward to install and they require the use of such force that damage to the sprinkler head often occurs.
When a fire has been brought under control the overhead sprinklers must be promptly inactivated to ensure that excess water will not inflict unnecessary damage. Many buildings are equipped with gravity-fed or pressure supplied water sources which discharge the fire-extinguishing fluid at rates which can flood a building within a relatively short period of time.
Accordingly, there is a need for a safe and effective device by which to ameliorate the damage which might result from a runaway sprinkler.
In U.S. Pat. No. 2,666,670, Vincent McGraw describes a closure device which installs easily and snaps away from the sprinkler head when the system is activated. However, this snap-away device has application only on dry sprinkler heads, that is, systems in which the heads do not contain a supply of fire-extinguishing fluid per se but which rely, instead, upon a water reservoir maintained at a remote source. The McGraw device has no application to wet sprinklers which contain within the head a supply of water for immediate discharge.
In U.S. Pat. No. 3,223,171, Walter DeGroot describes a closure plug comprised of telescoping members which are spring loaded. The spring has a compressive force which is at least equal to the force exerted by the water in the supply line to ensure that the plug will not be rejected. This plug is installed by the use of a mounting pole equipped with a triggering mechanism.
The DeGroot plug is neither inexpensive to manufacture or practical in its application because, in time, the spring assembly corrodes or loses its resiliency and becomes inoperable. Moreover, the inserted plug remains fixed and, as a consequence, the system cannot be reactivated until the plug is removed by hand.
From the foregoing it is obvious that a need exists for a closure device which can be used to terminate the flow of water from an activated sprinkler head in an effective, safe, convenient and inexpensive manner.
Moreover, there is a need for a closure device which can be allowed to remain on a sprinkler head in an inconspicuous manner and which does not require manual removal.
The present invention fills these needs by providing a closure device which can be manufactured inexpensively, installed easily and transported in volume without difficulty.